Convergence of marine megafauna movement patterns in coastal and open oceans

The extent of increasing anthropogenic impacts on large marine vertebrates partly depends on the animals’ movement patterns. Effective conservation requires identification of the key drivers of movement including intrinsic properties and extrinsic constraints associated with the dynamic nature of the environments the animals inhabit. However, the relative importance of intrinsic versus extrinsic factors remains elusive. We analyze a global dataset of ∼2.8 million locations from >2,600 tracked individuals across 50 marine vertebrates evolutionarily separated by millions of years and using different locomotion modes (fly, swim, walk/paddle). Strikingly, movement patterns show a remarkable convergence, being strongly conserved across species and independent of body length and mass, despite these traits ranging over 10 orders of magnitude among the species studied. This represents a fundamental difference between marine and terrestrial vertebrates not previously identified, likely linked to the reduced costs of locomotion in water. Movement patterns were primarily explained by the interaction between species-specific traits and the habitat(s) they move through, resulting in complex movement patterns when moving close to coasts compared with more predictable patterns when moving in open oceans. This distinct difference may be associated with greater complexity within coastal microhabitats, highlighting a critical role of preferred habitat in shaping marine vertebrate global movements. Efforts to develop understanding of the characteristics of vertebrate movement should consider the habitat(s) through which they move to identify how movement patterns will alter with forecasted severe ocean changes, such as reduced Arctic sea ice cover, sea level rise, and declining oxygen content

Convergence of marine megafauna movement patterns in coastal and open oceans

Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences of the United States of America 115 (2018): 3072-3077, doi:10.1073/pnas.1716137115.The extent of increasing anthropogenic impacts on large marine vertebrates partly depends on the animals’ movement patterns. Effective conservation requires identification of the key drivers of movement including intrinsic properties and extrinsic constraints associated with the dynamic nature of the environments the animals inhabit. However, the relative importance of intrinsic versus extrinsic factors remains elusive. We analyse a global dataset of 2.8 million locations from > 2,600 tracked individuals across 50 marine vertebrates evolutionarily separated by millions of years and using different locomotion modes (fly, swim, walk/paddle). Strikingly, movement patterns show a remarkable convergence, being strongly conserved across species and independent of body length and mass, despite these traits ranging over 10 orders of magnitude among the species studied. This represents a fundamental difference between marine and terrestrial vertebrates not previously identified, likely linked to the reduced costs of locomotion in water. Movement patterns were primarily explained by the interaction between species-specific traits and the habitat(s) they move through, resulting in complex movement patterns when moving close to coasts compared to more predictable patterns when moving in open oceans. This distinct difference may be associated with greater complexity within coastal micro-habitats, highlighting a critical role of preferred habitat in shaping marine vertebrate global movements. Efforts to develop understanding of the characteristics of vertebrate movement should consider the habitat(s) through which they move to identify how movement patterns will alter with forecasted severe ocean changes, such as reduced Arctic sea ice cover, sea level rise and declining oxygen content.Workshops funding granted by the UWA Oceans Institute, AIMS, and KAUST. AMMS was supported by an ARC Grant DE170100841 and an IOMRC (UWA, AIMS, CSIRO) fellowship; JPR by MEDC (FPU program, Spain); DWS by UK NERC and Save Our Seas Foundation; NQ by FCT (Portugal); MMCM by a CAPES fellowship (Ministry of Education)

Proteoglycan changes in carcinogen (4WQ0)-Treated tongue mucosa

The purpose of this study was to undertake preliminary analyses of the extracellular proteoglycans in carcinogen [4-nitroquinoline N-oxide (4NQO)]-treated rat tongue mucosa. Experimental rats were exposed to twice-weekly applications of 4NQO in propylene glycol for six months, after which the animals were killed. Control and 4NQO-treated tissues were subjected to sequential aqueous extractions of proteoglycans under associative and dissociative conditions, followed by alkaline cleavage of protein-glycosaminoglycan linkages to yield a glycosaminoglycan residue. Tissues subjected to 4NQO applications contained smaller proportions of proteoglycans which were readily soluble under associative and dissociative conditions. Proportionately more proteoglycan remained strongly associated with other intercellular tissue components, being released only by alkaline cleavage. These biochemical alterations in preinvasive 4NQO-treated epithelium and connective tissues, together with an observed associated change in water retention by the connective tissue, occurred prior to actual neoplastic invasion and suggest differences in macromolecular conformation and orderliness. We hypothesize that these changes are related to the phenomenon of neoplastic epithelial invasion

Antigen retrieval for electron microscopy using a microwave technique for epithelial and basal lamina antigens

The current study extends the principles of the antigen retrieval technique for formalin-fixed, paraffin-embedded tissues to transmission electron microscopy. Specimens prepared for both routine and immunoultrastructural studies were examined for the effects of microwave treatment on the immunolabeling of tissue antigens. Specimens of normal rat tongue mucosa and human oral mucosa were microwaved before immunogold labeling was done using six types of antibody (types I, III, IV, and VI collagen, laminin, and cytokeratin). Sections were cut from tissue blocks that had been fixed and embedded for either ultrastructural immunocytochemistry in L.R. White resin or routine electron microscopic morphology in TAAB resin. Compared with nonmicrowaved sections, microwave-treated, immunolabeled sections of both types of embedded tissues revealed markedly enhanced gold labeling for type IV collagen in the oral epithelial basal lamina. Moreover, microwave-treated L.R. White sections showed greater label density for type III and VI collagens and for cytokeratin compared with nonmicrowaved sections. There was variable gold labeling for laminin in both TAAB and L.R. White sections with or without microwave pretreatment and no improvement in type I collagen detection in microwave-treated sections. We concluded that postembedding microwave treatment of plastic ultrathin sections on sodium citrate buffer enhances some tissue antigens by increasing the likelihood of reexposing epitopes encrypted by a fixative-denaturative milieu. This microwave technique offers the potential of combining immunocytochemistry with enhanced exposure of antigenic markers of ultrastructural morphology in a number of extracellular sites

Studying root development in soil using DNA technology: idea to impact

Quantitative DNA assays for measuring root distribution and seed banks in soil are under development for wheat, barley, ryegrass, subterranean clover, phalaris and lucerne. These assays have potential to determine root distributions in soil profiles in either monoculture or mixed sward systems. The assays quantify DNA from live cells only and many of these cells will be in fine roots, prone to loss during soil washing with conventional root assessment procedures. In pot experiments the ryegrass DNA assay showed a rapid decline in soil root DNA over 10 days following plants being either defoliated or sprayed with glyphosate. This response is most likely due to DNA degrading in dying root cells. DNA assays for wheat and barley have also been used to assess genetic differences in root architecture under drought conditions and at field sites with hostile subsoils. The assays for pasture species have been used to measure differences in root distribution of pasture species in lime amended plots at the MASTER site (NSW DPI, Wagga Wagga). Results from the above studies show that quantitative DNA assays combined with high throughput DNA extraction systems are potentially useful to determine distribution of root systems under field conditions. This paves the way for high-throughput root phenotyping and incorporation of root architecture traits into breeding programs to improve drought tolerance as one possible role for the technology. In pasture trials the assays have the capacity to measure the impact of different management systems on specific species in mixed swards.Alan McKay, Ian T. Riley, Di Hartley, Sue Wiebkin, Herdina, Guangdi Li, Stewart Coventry, Sharla Hall, and Chunyuan Huan

Comparative biology of tropical Lethrinus species (Emperors): challenges for multi-species management

Life-history characteristics of six tropical Lethrinus species sampled from the Great Barrier Reef World Heritage Area were compared. Two species groups were identified based on fork length (LF): large species with maximum LF > 640 mm (longface emperor Lethrinus olivaceus, yellowlip emperor Lethrinus xanthochilus and spangled emperor Lethrinus nebulosus) and small species with maximum LF < 480 mm (Pacific yellowtail emperor Lethrinus atkinsoni, pink ear emperor Lethrinus lentjan and ornate emperor Lethrinus ornatus). Lifespan was not correlated with LF. Early growth for all species was rapid and similar during the first few years of life, but coefficients of the von Bertalanffy growth function varied considerably among species. Growth also differed between sexes for L. atkinsoni. Reproductive characteristics varied among species, with peak periods of spawning occurring in November to December for L. atkinsoni, July to August for L. nebulous, September to October for L. olivaceus and a protracted season for L. lentjan, although fewer samples were available for the last two species. Sex-specific LF and age distributions and gonad histology of L. lentjan were suggestive of a functional protogynous reproductive pattern, as observed in other lethrinids. Gonad histology indicated non-functional protogynous hermaphroditism for L. atkinsoni and L. nebulosus. The diversity of life histories among these closely related species emphasizes the difficulty in devising single management strategies appropriate for multi-species fisheries and illustrates the importance of understanding species-specific life histories to infer responses to exploitation